Recently, I acquired a 1985 Mercedes-Benz 190E 2.3 8V Grey Market model with 105,000 miles on the odometer. Just a week into ownership, I encountered a minor transmission issue that necessitated replacing the transmission coolant lines, filter, and gasket. It turned out the previous owner wasn’t entirely forthcoming about the car’s history – a stark contrast to my prior experience with a 1991 Mazda Miata (formerly owned by General David Petraeus, but that’s a story for another time).
Shortly after resolving the transmission concerns, a new issue arose: my ’85 Baby Benz began to overheat, creeping past the 85 degrees Celsius mark in typical stop-and-go traffic. Upon inspecting the engine bay with the hood raised, I observed the primary cooling fan – a large, five-bladed, yellowish fan – in operation. However, its speed seemed insufficient; I could easily stop it with my hand. Being new to the intricacies of the Mercedes-Benz W201, I consulted a more knowledgeable friend. His diagnosis pointed towards a failing fan clutch and potentially a worn water pump.
Acting on this advice, I procured aftermarket replacement parts. The shopping list included a $70 water pump from Autozone, a $40 electromagnetic fan clutch, a $25 thermostat, $25 of Mercedes Blue Coolant, and $100 for a mobile mechanic to handle the installation. The mechanic, initially quoting $100 without fully assessing the job, seemed less than pleased when the repair stretched to four hours.
With all the new components installed, we ran into an unexpected snag. The factory Engine Cooling Fan Sensor, designed to screw into the side of the original water pump, was incompatible with the new, albeit exact replacement, water pump. Another trip to purchase a $35 Engine Cooling Fan Sensor became necessary – a small price to pay, I reasoned, compared to the catastrophic consequences of an overheated engine.
Now, the crucial question remains: does the Engine Cooling Fan Sensor, located on the water pump, directly control the engagement of the fan clutch? Or is there another sensor responsible for triggering the fan clutch? Post-repairs, the car’s overall performance has improved. However, the main yellowish cooling fan doesn’t seem to spin with the robust, forceful pace one would expect – the kind that would discourage any hand-testing.
For comparison, my other vehicle, a heavily modified 1966 Ford Mustang Fastback with a ’03 SVT Cobra supercharged engine swap, experienced a similar water pump issue. In that instance, a simple water pump replacement rectified the problem entirely, restoring the fan to its proper function.
